Online helix adjustment to control connector location on preconnectorized tapered assemblies

ABSTRACT

Embodiments of the disclosure relate to a method of preparing a bundled cable. In the method, a plurality of subunits is wound around a central member in one or more layers of subunits to form the bundled cable. For a section of the central member, each layer of subunits has a pitch over which a subunit of the layer of subunits makes one revolution around the section of the central member and a length of the subunit required to make the one revolution. The subunits are configured to have a nominal helical length equal to the ratio of a nominal length to a nominal pitch. Further, in the method, a measurement of the bundled cable is monitored, and a winding rate of the plurality of subunits is adjusted based on the measurement in order to account for deviations from the nominal helical length.

CROSS-REFERENCED TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 17/002,883 filed Aug. 26, 2020, which claims the benefit ofpriority under 35 U.S.C. § 119 of U.S. Provisional Application Ser. No.62/895,219 filed on Sep. 3, 2019, the content of which is relied uponand incorporated herein by reference in its entirety.

BACKGROUND

The disclosure relates generally to optical fiber cables and moreparticularly to optical fiber cables that have drop cables that runalong at least a portion of the length of a main distribution cable.Optical fiber cables are used to transmit data over distance. Generally,large distribution cables that carry a multitude of optical fibers froma hub are sub-divided at network nodes, which are further sub-divided,e.g., to the premises of individual subscribers. Generally, thesesubdivisions involve splicing a cable tether into a main distributionline. Cable splicing at specific locations along a main distributionline is a delicate and time consuming process that requires preciseplacement of the cable tether and that involves the risks of cutting thewrong fibers and providing environmental exposure to the cable interior.

SUMMARY

In one aspect, embodiments of the disclosure relate to a method ofpreparing a bundled cable. In the method, a plurality of subunits iswound around a central member in one or more layers of subunits to formthe bundled cable. For a section of the central member, each layer ofsubunits has a pitch over which a subunit of the layer of subunits makesone revolution around the section of the central member and a length ofthe subunit required to make the one revolution. The subunits areconfigured to have a nominal helical length equal to the ratio of anominal length to a nominal pitch. Further, in the method, a measurementof the bundled cable is monitored, and a winding rate of the pluralityof subunits is adjusted based on the measurement in order to account fordeviations from the nominal helical length.

In another aspect, embodiments of the disclosure relates to a method ofpreparing a bundled cable. In the method, a central member is providedhaving an outer central member surface defining a central memberdiameter. A plurality of subunits is provided. Each of the plurality ofsubunits has an outer subunit surface defining a subunit diameter. Inthe method, the subunit diameter and the central member diameter aremonitored. The plurality of subunits is wound around a central member inone or more layers of subunits to form the bundled cable. For a sectionof the central member, each layer of subunits has a pitch over which asubunit of the layer of subunits makes one revolution around the sectionof the central member and a length of the subunit required to make theone revolution. The subunits are configured to have a nominal helicallength equal to the ratio of a nominal length to a nominal pitch. Awinding rate of the plurality of subunits is adjusted based on themonitoring of the subunit diameter and of the central member diameter inorder to account for deviations from the nominal helical length.

In still another aspect, embodiments of the disclosure relates to asystem for preparing a bundled cable. The system includes a payoff reelconfigured to provide a run of a central member, a strander configuredto wind a plurality of subunits around the central member to form thebundled cable, and a monitoring system configured to take at least onemeasurement of at least one of the central member, the plurality ofsubunits, or the bundled cable. The strander is configured to adjust awinding rate for the plurality of subunits based on the measurement fromthe monitoring system.

In yet another aspect, embodiments of the disclosure relate to a bundledoptical fiber cable. The bundled optical fiber cable includes a centralmember having a first end and a second end. The first end and the secondend define a length of the bundled optical fiber cable. The bundledoptical fiber cable also includes plurality of subunits wound around thecentral member. Each of the plurality of subunits includes a subunitjacket having an inner surface and an outer surface. The inner surfacedefines a central bore containing at least one optical fiber. Theplurality of subunits have a variable pitch along the length of thecentral member, and the outer surface of the subunit jacket of each ofthe plurality of subunits is an outermost surface of the bundled opticalfiber cable.

Additional features and advantages will be set forth in the detaileddescription which follows, and in part will be readily apparent to thoseskilled in the art from the description or recognized by practicing theembodiments as described in the written description and claims hereof,as well as the appended drawings.

It is to be understood that both the foregoing general description andthe following detailed description are merely exemplary, and areintended to provide an overview or framework to understand the natureand character of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding and are incorporated in and constitute a part of thisspecification. The drawings illustrate one or more embodiment(s), andtogether with the description serve to explain principles and operationof the various embodiments.

FIG. 1 depicts partial perspective view of a bundled optical cable,according to an exemplary embodiment.

FIG. 2 depicts a cross-sectional view of the bundled optical cable ofFIG. 1 .

FIGS. 3A-3B are schematic depictions of an aerial installation and aduct installation of a bundled optical fiber, according to an exemplaryembodiment;

FIG. 4 provides a schematic representation of the geometric relationshipbetween a subunit and a central member during winding, according to anexemplary embodiment;

FIG. 5 depicts another geometric relation pertaining to the helicallength of the stranded unit, according to an exemplary embodiment;

FIG. 6 depicts a cross-section of a bundled cable demonstrating the rdimension, according to an exemplary embodiment;

FIG. 7 is a schematic depiction of a system for performing a windingrate adjustment, according to an exemplary embodiment; and

FIGS. 8A-8B depict an embodiment of subunit indexing to provide adesired helical length, according to an exemplary embodiment.

DETAILED DESCRIPTION

Referring generally to the figures, various embodiments of a method forproducing a bundled optical fiber cable are provided. A bundled opticalfiber cable includes a plurality of subunits wound around a centralmember, and each of the plurality of subunits is configured to branchfrom the cable at a particular branching point along the length of thecable. These cables provide the advantage of being assembled andconnectorized in the factory such that the bundled optical fiber cablecan be easily deployed without labor-intensive splicing in the field.However, the subunit length must be precise in order that theconnectorized end accurately corresponds to drop points in the field. Inthis regard, the components of the cable have nominal dimensions, butoften, the components deviate in dimension by fractions of a millimeter.Over the length of a cable (e.g., a 1 kilometer (km) cable), these smalldeviations in component size add up to a large deviation in the subunitlength and, ultimately, the position of the connectorized end. Incertain instances, the deviations in length can be tens of inches.

To account for the deviation in component dimensions, according to thepresent disclosure, the dimensions of the components prior to winding orthe dimensions of the bundled cable after winding are determined. Thesedimensions are used to adjust the winding rate of the subunits aroundthe central member to ensure that the connectorized ends are accuratelyterminated at a desired position relative to the branch point. Forexample, if the connector is running long, the winding rate is increasedto decrease the laylength, using more of the subunit, and conversely, ifthe connector is running short, the winding rate is decreased toincrease the laylength, using less of the subunit. Advantageously, thewinding rate can be changed without changing the lines speed at whichthe central member and subunits are being pulled through the windingsystem. Other aspects and advantages will be described in relation tothese and other embodiments provided herein and in the figures. Theseembodiments are presented by way of illustration and not by way oflimitation.

FIG. 1 depicts an embodiment of a bundled optical fiber cable 10 in apartial sectional view taken over a portion of the length of the bundledoptical fiber cable 10. As can be seen, the bundled optical fiber cable10 includes a central member 12 (e.g., an optical fiber cable or anovercoated strength element) and a plurality of subunits 14 that arewound around the outside of the central member 12. In embodiments, thesubunits 14 are helically wound around the central member 12. Forexample, in embodiments, the subunits 14 may have an S-winding or aZ-winding around the central member 12. Additionally, in embodiments,the subunits 14 may have an SZ winding around the central member 12.That is, the subunits 14 may have an S-winding followed by a reversal toa Z-winding, then a reversal to S-winding, etc.

FIG. 2 provides a detailed cross-sectional view of an embodiment of thebundled cable 10. As can be seen, the subunits 14 are substantiallyevenly spaced around a circumference of the central member 12. Inembodiments, the central member 12 may be an optical fiber cable (asshown in FIG. 2 ), a power transmission cable, or a central strengthmember (e.g., a glass-reinforced plastic (GRP) rod optionally jacketedwith a polymeric material).

In the embodiment depicted, the bundled cable 10 includes thirteensubunits 14. In embodiments, as few as a single subunit 14 can beprovided around the central member 12. In general, the maximum number ofsubunits 14 that can be provided around the central member 12 is limitedby the installation parameters (e.g., duct size) or manufacturingcapabilities (e.g., winding equipment) for the bundled cable 10. Forinstance, given an installation parameter of a two inch duct size, themaximum number of subunits 14 that can be provided around the centralmember 12 may be thirty-nine subunits in embodiments. In still otherembodiments, the subunits 14 are arranged in multiple layers around thecentral member 12. Taking the two inch duct again as an example, thebundled cable 10 may include an innermost layer of the seven subunits 14around a jacketed GRP rod central member 12 with an intermediate layerof thirteen subunits 14 and an outer layer of another nineteen subunits14 (7+13+19=39 subunits). In embodiments, the subunits 14 containoptical fibers and/or power transmission elements. Additionally, inembodiments, the subunits 14 may be “dummy cables” that do not containany optical fibers or power transmission element but which providestructural support around the cable.

FIG. 2 depicts the structure of an embodiment of a bundled cable 10 inwhich the central member 12 is an optical fiber cable and the subunits14 are drop cables. In the embodiment depicted, the central member 12includes an outer jacket 16 having an inner surface 17 and an outersurface 18. In the embodiment depicted, the inner surface 17 defines acable bore 19 within which a plurality of optical fibers 20 aredisposed. The optical fibers 20 can be arranged in a variety of suitableways within the central member 12. In the embodiment depicted, theoptical fibers 20 are arranged in a stack 21 of ribbons 22. Inparticular, the optical fibers 20 are arranged into a stack 21 ofsixteen ribbons 22, defining a plus-shaped cross-section. In theembodiment depicted, the total number of optical fibers 20 in the stack21 of ribbons 22 is 288. In embodiments, a single stack can contain upto 864 optical fibers 20. As shown in FIG. 2 , the stack 21 issurrounded by a stack wrap 24, which, in embodiments, may provide colorcoding for multiple-stack configurations and/or water-blockingproperties. In embodiments, the central member 12 includes multiplestacks 21, e.g., from one stack to twelve stacks. Central members 12 ofthe type described are available from Corning Incorporated, Corning,N.Y., such as those marketed under the trademark RocketRibbon™.Alternatively, the optical fibers 20 may be arranged in a central tube(or a plurality of buffer tubes) in a loose tube configuration. Centralmembers 12 of this type are available from Corning Incorporated,Corning, N.Y., such as those marketed under the trademarks ALTOS®,SST-Ribbon™, and SST-UltraRibbon™.

As can also be seen in the embodiment depicted in FIG. 2 , the subunits14 each include a plurality of optical fibers 20 disposed within acentral tube 26. In embodiments, the subunits 14 contain from oneoptical fiber 20 up to thirty-six optical fibers 20 depending on theparticular needs of the installation. In embodiments, the central tube26 is surrounded by a plurality of tensile elements 28 (e.g., yarns ofaramid, glass, and/or basalt fibers). The tensile elements 28 aresurrounded by a subunit jacket 30. In embodiments, the subunit jacket 30has an outer surface 32, and for the subunits 14 immediately surroundingthe central member 12, the outer surface 32 of the subunits 14 contactsthe outer surface 18 of the outer jacket 16 of the central member 12. Inembodiments, the subunits 14 may be bonded (e.g., welded or adhered) tothe central member 12 at one or more locations along the length of thecentral member 12. Further, in embodiments, the outer surface 32 of thesubunit jacket 30 may define an outermost surface of the bundled cable10. That is, no further jacketing material is applied around thesubunits (not including any periodically spaced bindings, wraps, or tieswhich may be used to keep the subunits 14 bound to the central member12).

FIGS. 3A and 3B depict a schematic representation of a bundled cable 10with a subunit 14 branching from the central member 12 at a branch point34. To provide enough slack to make a connection at the branch point(TBP) 34 and to properly position the subunit 14, the subunit 14 isterminated at a particular location along the length of the bundledcable 10. As shown in FIGS. 3A and 3B, the bundled cable 10 may bemarked with a pole alignment marker (PAM) 36. During installation, thebundled cable 10 is positioned such that the pole alignment marker 36 issubstantially centered on an installation pole or other alignmentstructure. As can be seen, the subunits 14 in the bundled cables 10shown in FIGS. 3A and 3B are preconnectorized with a connector 38. Inthe embodiment shown, the connectors 38 are attached to the bundledcable 10 with a tie wrap 40.

Depending on the type of installation, the subunit 14 may be terminatedat different lengths. FIG. 3A depicts the layout for an aerialinstallation, and FIG. 3B depicts the layout for a duct installation. Ascan be seen, for both layouts, the branch point 34 may be positionedwithin about 5 ft (+/−6 in) from the pole alignment marker 36. In theaerial layout of FIG. 3A, the subunit 14 nominally terminates about 1 ft(+/−6 in) prior to the pole alignment marker 36. In the duct layout ofFIG. 3B, the subunit 14 terminates nominally about 5 ft (+/−6 in) pastthe pole alignment marker 36. As will be discussed below, a variety offactors dictate whether the subunits 14 are able to be accuratelypositioned at the nominal termination points along the length of thebundled cable 10 such that during installation the subunits 14 will belocated at the desired position relative to the pole alignment marker36.

Because the subunits 14 are wound around a central member 12, theactual, fully-extended length of the subunits 14 is longer than thelength along the central member 12. FIG. 4 illustrates this point with adepiction of a single subunit 14 wound around a central member 12. Toaccurately position the connector 38 along the bundled cable 10, thetotal length of each subunit 14 prior to winding needs to be known.Otherwise, the winding machine has to be stopped when the desiredtermination point is reached so that the subunit 14 can be connectorizedon-line. As shown in FIG. 4 , the winding of the subunit 14 around thecentral member 12 defines a pitch circle having radius r. Further, thelength over which the subunit 14 completes one revolution around thecentral member 12 is referred to as the pitch P (which is also known as“laylength”). The extended length of subunit 14 necessary to completeone revolution is referred to as the length L, and the length L can bedetermined through a relationship between the radius r of the pitchcircle and the pitch P as shown in FIG. 5 . In particular, the length Lis the hypotenuse of a right triangle having a first side length of Pand a second side length of 2πr. Accordingly, from FIGS. 4 and 5 , itcan be seen that at least two factors that directly affect length L arepitch P and radius r. Other factors that affect length L will bediscussed below but include forces that elongate the subunit 14 orcentral member 12 or introduce additional twist (affecting pitch P)).

Specifically, from the geometric relationship shown in FIG. 5 , a ratiobetween the length L and pitch P, referred to as the helical length HL(L/P=HL), can be determined from the pitch P and radius r based on thefollowing equation:

${H\; L} = \sqrt{1 + \left( \frac{2\pi r}{P} \right)^{2}}$

In general, pitch P is nominal based on the cable design, and thus, themain variable affecting helical length HL is the radius r of the pitchcircle. That is, during cable stranding, the machinery will be set up toproduce a specified pitch P, but as will be discussed below, smalldeviations in radius r ultimately affect the actual pitch P of thesubunit as stranded around the central member 12. As can be seen in FIG.6 , the radius r of the pitch circle is essentially equal to the sum ofthe radius r_(su) of the subunit 14 and the radius r_(cm) of the centralmember 12. While each of the subunit 14 and the central member 12 has anominal diameter, the diameter is variable over the length of eachsubunit 14 and central member 12 in practice, e.g., resulting fromvariability in the extrusion process.

To demonstrate the effect that even a small variation in the diameter ofthe central member 12 has on the helical length HL of the subunit 14, asimulation was performed with a bundled cable 10 having six subunits 14stranded around a jacketed GRP central member 12. In the simulation,each subunit 14 has a nominal outer diameter of 4.0 mm, and the centralmember 12 has a nominal outer diameter of 4.4 mm. A variability of+/−0.1 mm in the diameter of the central member 12 was considered. Thesimulation was a Monte Carlo simulation involving 5000 iterations ofwinding subunits having a 4.0 mm diameter helically around centralmembers 12 having a normal distribution of diameters between 4.3 mm and4.5 mm (i.e., nominal 4.4 mm with +/−0.1 mm deviation). According to thesimulations, a connector movement of +/−2 inches developed over 100meters (m). Thus, over the length of a 300 m cable, the deviation wouldalready be at the level of tolerance discussed above with respect toaerial and duct installations described in relation to FIGS. 3A and 3B.As the length of the bundled cable grows, the connector movementincreases. For example, a cable that is 1 km long would have a connectordisplacement of as much as 20 inches.

Moreover, this simulation only considered one source of deviation (thediameter of the central member 12). The diameters of the subunits 14could also vary along their length. Besides the dimensions of thecomponents of the bundled cable 10, other factors affect the actualpitch and helical length of the subunits 14. The tension at which thecentral member 12 and subunits 14 are pulled through the processing lineaffects their lengths during the stranding operation. For example, ahigher tension will create more elongation in the central member 12and/or subunits 14 than a lower tension during stranding. Afterstranding, there may be a relaxation that causes the central member orsubunits 14 to shrink back, affecting pitch. Further, the stranding andpulling of the cable creates torsional error that affects pitch. Whenmultiple factors are considered, the deviation in connector placementincreases to about 3.5 inches per 100 m. Additionally, in embodiments inwhich multiple layers of subunits are provided, the deviation inconnector placement can increase further still. As shown in FIG. 6 , thesubunits 14 have a small gap between them around the circumference ofthe central member 12. In outer layers, this gap can become compressed,leading to an additional source of deviation. In addition, deviation inconnector placement in a second layer can be as much as about 5.7 inchesper 100 m and in a third layer can be as much as about 6.2 inches per100 m.

To accommodate the potentially large deviations in the position of thesubunits as the result of small deviations in the dimensions of thesubunits, monitoring the dimensions of the subunits and/or centralmember as the subunits are wrapped around the central member andadjusting the rate at which the subunits are wound around the centralmember is employed. FIG. 7 depicts a system 100 for adjusting thewinding rate. In the system 100, the central member 12 is carried on apayoff reel 110. The central member 12 runs through a strander 120, suchas a rigid or planetary strander, which winds or wraps the subunits 14around the central member 12. The central member 12 and subunits 14 passthrough a closing point 130 to create the bundled cable 10. The bundledcable 10 is pulled by a caterpuller 140, and the bundled cable 10 istaken up on a take-up reel 150. In other embodiments, the strander 120could be a drum twist strander that rotates the payoff and takeup reels110, 120 in lieu of rotating the outer subunits 14 around the centralmember 12.

To adjust the winding rate, the diameter of the central member 12, thediameter of the subunits 14, the diameter of the bundled cable 10,and/or the pitch P of the subunits 14 are monitored. For example, asshown in FIG. 7 , the system 100 includes monitoring stations 160 a, 160b, and 160 c. Monitoring station 160 a is positioned upstream of thestrander 120 to capture the diameter of the central member 12.Monitoring station 160 b is positioned proximate to the strander 120(e.g., near the subunit feed for the strander 120) in order to capturethe dimensions of the subunits 14. Further, monitoring station 160 c ispositioned after the closing point 130 to capture the dimensions of thebundled cable 10 or to capture the pitch P of the subunits 14. Inembodiments, only monitoring station 160 c is used, and the dimensionsof the bundled cable 10 are used to adjust the winding rate for theupstream cable. In other embodiments, only monitoring stations 160 a and160 b are used to measure the dimensions of the individual components toadjust the winding ratio downstream of the monitoring stations 160 a,160 b.

In embodiments, the monitoring stations 160 a, 160 b, 160 c directlymeasure the dimensions of the central member 12, subunits 14, and/orbundled cable 10 using a probe, such as a non-contact laser. Inembodiments used in conjunction with the measuring probes, a visionsystem may be located at monitoring station 160 c that measures thepitch (or laylength) by capturing images of the bundled cable 10. Thevision system compensates for errors in the laylength based on torsionaleffects leading into the caterpuller 140. Another way to measure thecorrect location for landing the connector is by measuring length of theindividual subunits as well as the length of the central member andadjusting the laylength based on maintaining a desired ratio between thelengths.

By monitoring the dimensions of the bundled cable 10 or cable component,the winding rate of the strander 120 can be adjusted to increase ordecrease the pitch P so that the connector is accurately positioned inrelation to pole access markers along the length of the bundled cable10. Advantageously, the feed rates of the central member 12 and subunits14 do not have to be adjusted, which allows for the desired productionrate to be maintained despite deviations in component size. Thus, usinga system 100 as depicted in FIG. 7 , the minor deviation in componentdimensions can be accommodated through adjusting of the winding rate asshown in Table 1, below.

In Table 1, a bundled cable having a subunit diameter of 4.0 mm was usedwith a central member having a nominal diameter of 4.4 millimeters (mm).The laylength (pitch P) for such a cable was 125 mm. As can be seen in acomparison of Example 1 (no deviation) and Examples 2 and 3 (negativedeviation and positive deviation, respectively), each bundled cable hadno deviation in length (L). However, the winding rate was increased by1.9 rpm for Example 2 and decreased by 1.9 rpm for Example 3. Thewinding rates caused Example 2 to have a shorter pitch than Example 1and caused Example 3 to have a longer pitch than Example 1.

TABLE 1 Properties of Subunits and Central Member used in Bundled CableSimulations Ex. 1 Ex. 2 Ex. 3 Unit Diameter (mm) 4.0 4.0 4.0 Layer 1Units 6 6 6 Central Member Diameter (mm) 4.4 4.3 4.5 Layer 1 Pitch (mm)125.00 123.51 126.49 Layer 1 Helical Length (HL or L/P) 1.022 1.0221.022 Helix length variation (in/100 m) 0.000 0.000 0.000 Rotationalspeed (rpm) 160.0 161.9 158.1

Besides winding rate, the final properties of the bundled cable can beinfluenced by providing accurately cut subunits for winding around thecentral member 12. FIGS. 8A and 8B depict an embodiment of an indexedsubunit 14. As can be seen in FIG. 8A, the subunit 14 includes a numberof coordinated index marks 170 a, 170 b, 170 c. Each set of index marks170 a, 170 b, 170 c is separated by the desired total length TL of thesubunit 14. In preparing the subunit 14 for winding, the subunit 14 isconnectorized at an end. As shown in FIG. 8A, the subunit 14 has apreselected connectorization index point and a corresponding index pointfor trimming the subunit to length. Accordingly, if a successfulconnectorization is made at index mark 170 a, the subunit 14 is trimmedat the corresponding index mark 170 a at the opposite end of the subunitto provide the desired total length TL of the subunit 14 as shown inFIG. 8B. If the connectorization at index mark 170 a is not successful,then connectorizaion is attempted at index mark 170 b, and so on, andthe corresponding index mark is used to trim the subunit 14 to thedesired length thereafter.

Unless otherwise expressly stated, it is in no way intended that anymethod set forth herein be construed as requiring that its steps beperformed in a specific order. Accordingly, where a method claim doesnot actually recite an order to be followed by its steps or it is nototherwise specifically stated in the claims or descriptions that thesteps are to be limited to a specific order, it is in no way intendedthat any particular order be inferred. In addition, as used herein thearticle “a” is intended include one or more than one component orelement, and is not intended to be construed as meaning only one.

It will be apparent to those skilled in the art that variousmodifications and variations can be made without departing from thespirit or scope of the disclosed embodiments. Since modificationscombinations, sub-combinations and variations of the disclosedembodiments incorporating the spirit and substance of the embodimentsmay occur to persons skilled in the art, the disclosed embodimentsshould be construed to include everything within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A bundled optical fiber cable, comprising: acentral member having a first end and a second end, the first end andthe second end defining a length of the bundled optical fiber cable; aplurality of subunits wound around the central member, each of theplurality of subunits comprising a subunit jacket having an innersurface and an outer surface, wherein the inner surface defines acentral bore containing at least one optical fiber; wherein theplurality of subunits have a variable pitch along the length of thecentral member; and wherein the outer surface of the subunit jacket ofeach of the plurality of subunits is an outermost surface of the bundledoptical fiber cable; wherein the bundled optical fiber cable is anaerial cable and wherein the bundled optical fiber cable comprises aplurality of pole alignment markers along the length of the bundledoptical fiber cable; wherein each of the plurality of subunits branchesfrom the central member at a branch point located within five feet of apole alignment marker of the plurality of pole alignment markers; andwherein each of the plurality of subunits is configured to terminatewithin 6 inches of a nominal termination point located towards the firstend of the bundled optical fiber cable and one foot from a polealignment marker of the plurality of pole alignment markers.
 2. Thebundled optical fiber cable of claim 1, wherein the central membercomprises at least one of an optical fiber cable comprising an outerjacket surrounding a plurality of optical fibers or a central strengthmember comprising a strength element and an outer jacket formed aroundthe strength element.
 3. A bundled optical fiber cable, comprising: acentral member having a first end and a second end, the first end andthe second end defining a length of the bundled optical fiber cable; aplurality of subunits wound around the central member, each of theplurality of subunits comprising a subunit jacket having an innersurface and an outer surface, wherein the inner surface defines acentral bore containing at least one optical fiber; wherein theplurality of subunits have a variable pitch along the length of thecentral member; and wherein the outer surface of the subunit jacket ofeach of the plurality of subunits is an outermost surface of the bundledoptical fiber cable; wherein the bundled optical fiber cable is a ductcable and wherein the bundled optical fiber cable comprises a pluralityof pole alignment markers along the length of the bundled optical fibercable; wherein each of the plurality of subunits branches from thecentral member at a branch point located within five feet of a polealignment marker of the plurality of pole alignment markers; and whereineach of the plurality of subunits is configured to terminate within 6inches of a nominal termination point located towards the second end ofthe bundled optical fiber cable and five feet from a pole alignmentmarker of the plurality of pole alignment markers.